Dietary fiber and oligosaccharides from ginseng and process for preparation thereof

ABSTRACT

The present invention relates to dietary fibers and oligosaccharides from Ginseng and process for preparation thereof, more particularly, to a method of preparing the dietary fiber from Ginseng by extruding and centrifuging byproducts from Ginseng extract, in the meantime, preparing the oligosaccharides from Ginseng by treating byproducts from Ginseng extract with polysaccharides hydrolytic enzymes and the subsequent ultrafiltration. Thus it provides prominent effects in producing physiologically active materials such as the dietary fibers and oligosaccharides from the said byproducts in an environment-friendly manner.

TECHNICAL FIELD

The present invention relates to dietary fiber and oligosaccharidesproduced from ginseng and a process for preparation thereof, and toginseng dietary fiber and a process for preparing the ginseng dietaryfiber involving the extrusion of ginseng residue, and to ginsengoligosaccharides prepared by polysaccharide hydrolytic enzyme treatmentof ginseng residue.

BACKGROUND ART

Panax ginseng C. A Meyer is a plant grown in the fair east of Asia(Northern latitude 33-48: Korea, North Manchuria—a part of Russia) andit belongs to Araliaceae Panax according to the plant taxonomy. Inparticular, ginseng grown in Korea is called Korean ginseng and is knownto have excellent pharmaceutical properties. Ginseng products areclassified into undried ginseng, red ginseng, white ginseng and Taegukginseng according to the preparation process.

Ginseng is known to have good preventive and medical effects for variousadult health conditions such as arteriosclerosis, hypertension, stress,fatigue, stamina decrease, hypertension, climacteric diseases, diabetesmellitus, cancer, aging, etc. Nutrition 16(5), 391-392(2000); EuropeanJournal of Clinical Pharmacology, 55(8), 567-575(1999).

In industry, ginseng is extracted using solvents such as hot water oralcohols. Ginseng residue, which is a by-product of extracting ginseng,is a kind of dietary fiber consisting of polysaccharides. Even thoughginseng residue has the potential to be used as dietary fiber materialwith various physiological properties, it has been widely used as animalfeed or simply discarded.

Dietary fiber consisting of various non-starch polysaccharide componentssuch as cellulose, hemicellulose, pectin, etc. is not digested by humanenzymes. The most important factor which determines physiologicalactivity of dietary fiber is solubility (Food Technology, 41(2),81-85(1987)). Dietary fiber is classified into water-insoluble dietaryfiber and water-soluble dietary fiber. Water-insoluble dietary fiberexhibits physiological functions such as increasing the size ofexcrement, reducing the time required for digested food to pass throughthe intestines, inhibiting starch hydrolysis, delaying glucoseabsorption, etc., which is attributed to a large amount of waterabsorption when water-insoluble dietary fiber passes through digestiveorgans. In contrast, a three-dimensional gel structure constructed bywater-soluable dietary fiber delays the passage of food and preventsabsorption of glucose. In particular, it is well known thatwater-soluble dietary fiber functions to decrease blood cholesterollevels.

Oligosaccharides are carbohydrates with low molecular weight and areclassified into two groups according to the method used to produce them.Oligosaccharides such as isomalto-oligosaccharides,fructo-oligosaccharides, galacto-oligosaccharides, etc. are prepared byenzymatic bioconversion of sugars, while inulin oligosaccharides,alginate oligosaccharides, chitosan oligosuccharides, etc. are producedby hydrolysis of polysaccharides (Food Industry and Nutrition 3(1),18-23(1998)).

Oligosaccharides are physiologically active as a bifidogenic factor thataccelerates proliferation of useful intestinal microbes.Oligosaccharides produced by hydrolysis of polysaccharides have variousphysiological and pharmaceutical functions such as decreasing bloodcholesterol levels, killing bacteria, activating the immune system,preventing/inhibiting cancer, etc. (Lebensm. Wiss. Technol., 27,1-9(1996); Tren. Food Sci. Technol., 7, 353-368(1996)).

A plant cell wall is composed of polysaccharides such as cellulose,hemicelluloses, pectin, etc., lignin and glycoproteins. In most cases,these components do not exist in a free state but exist in awater-insoluble state because of strong covalent, hydrogen and ionicbonds (Korea Nutrition and Food Society, 23(2): 358-370(1994)). Thesolubilization of a plant cell wall structure existing in awater-insoluble state augments the content of water-soluable dietaryfiber, which improves physiological characteristics of dietary fiber.

Conventionally, the insoluble dietary fiber components in a plant cellwall can be hydrolyzed by acid or alkali solution at a high temperature.However, this chemical hydrolysis method has various industrial problemssuch as generation of waste water, container corrosion, generation ofunusable residues, structural damage of the cell wall component, etc.(Carbohydrate Research, 260, 283-296(1994)).

Therefore, there is need for the development of an environment-friendlysolubilization process to produce functional carbohydrate materials fromthe walls of plant cells. Mechanical or enzymatic solubilization methodsare good alternative ways to solubilize plant cell walls without usingchemical treatments.

An example of a mechanical solubilization method is an extrusionprocess. An extruder simultaneously performs a variety of processes suchas mixing, cooking, texturizing, drying, sterilizing, cooling, etc. in asingle apparatus. The extrusion process, providing high temperature,high pressure and high shear force, is commonly used for manufacturinganimal feed and processed food products such as noodles, cereals, etc.

The high shear force provided during the extruding process can also beeffectively used for mechanically solublizing the water-insolublepolysaccharide components in the plant cell walls (Journal of FoodScience, 63(5), 841-844(1998)). However, the technology to solubilizewater-insoluble plant cell walls by the extruding process has not yetbeen fully developed. In particular, the extruding process forsolubilizing insoluble ginseng cell walls has not yet been applied inindustry.

An enzymatic solubilizing method can also be used to effectivelysolubilize the polysaccharide components of plant cell walls usingpolysaccharide hydrolytic enzymes. Ginseng residue consists mostly ofpolysaccharides, so it is very possible to produce oligosaccharides withlow molecular weight by polysaccharide hydrolysis of ginseng residue.Ginseng polysaccharides are composed of cellulose, hemisellulose andpectin, and thus the hydrolysis of ginseng polysaccharides can bereadily accomplished by using cellulase, hemicellulase, pectinase, etc.

Since polysaccharide hydrolytic enzymes such as cellulose,hemicellulase, and pectinase are commercially available, the enzymatichydrolysis of polysaccharides can be applied easily for industrialpurposes. In particular, since these commercial enzymes are composed ofvarious complex enzymes, they can be more effectively used for thehydrolysis of plant cell walls consisting of complex polysaccharides.

Thus, the present invention is achieved by producing water-solubledietary fiber from ginseng residue by an extruding process that combineshigh shear force, high temperature and high pressure, and also byproducing ginseng oligosaccharides with low molecular weight from theginseng residue using polysaccharide hydrolytic enzymes.

Accordingly, it is an object of the present invention to provide amethod for producing dietary fiber economically from ginseng residueusing an extruder without chemical treatment, and ginseng dietary fiberprepared by the extruding process.

It is another object of the present invention to provide a method forpreparing oligosaccharides with low molecular weight from ginsengresidue by polysaccharide hydrolysis, and ginseng oligosaccharidesprepared by polysaccharide hydrolytic enzymes.

SUMMARY OF THE INVENTION

The above objects of the present invention were achieved by feedingginseng residue produced as a by-product of ginseng extraction into atwin screw extruder, extruding the ginseng residue by controlling thescrew speed, the feed rate and the moisture content; adding water to theextruded ginseng residue, mixing and centrifuging; and preparingwater-soluble ginseng dietary fiber from a supernatant andwater-insoluble ginseng dietary fiber precipitate obtained aftercentrifugation.

In addition, the above objects of the prevent invention were achieved byadding polysaccharide hydrolytic enzymes such as cellulase,hemicellulase and pectinase to the ginseng residue; hydrolyzingpolysaccharides in the ginseng residue; sequentially passing thepolysaccharide hydrolysates through an ultrafiltrator and fractionatingthe polysaccharide hydrolysates according to molecular weight; andobtaining ginseng oligosaccharides with low molecular weight.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become better understood by describing indetail preferred embodiments thereof with reference to the accompanyingdrawings in which:

FIG. 1 is a schematic view illustrating a process for preparing ginsengdietary fiber according to the present invention;

FIG. 2 a is a standard curve of gel permeation chromatography carriedout using pullulan as a standard material according to the presentinvention;

FIG. 2 b is a view illustrating a result of gel permeationchromatography that represents the molecular weight of water-solubleginseng dietary fiber according to the present invention;

FIG. 3 is a schematic view illustrating a process for preparing ginsengoligosaccharides according to the present invention;

FIG. 4 a is a standard curve of gel permeation chromatography carriedout using pullulan and lactose as standard materials according to thepresent invention;

FIG. 4 b is a view illustrating a result of gel permeationchromatography that represents the molecular weight of ginsengoligosaccharides according to the present invention; and

FIG. 5 is a growth curve of Bifidobacterium longum in a culture mediawith ginseng oligosaccharides according to the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The process for preparing dietary fiber from ginseng residue accordingto the present invention includes the first step of feeding the ginsengresidue into a twin screw extruder, the second step of adding water tothe extruded sample, agitating the same and centrifuging, the third stepof washing a precipitate by adding isopropanol to the supernatant andevaporating the same to thereby prepare water-soluble dietary fiber, andthe fourth step of drying a precipitate obtained from centrifugation inthe second step and preparing water-insoluble ginseng dietary fiber.

A preferred example of preparing dietary fiber from ginseng residueaccording to the present invention is illustrated in FIG. 1. As shown, atwin-screw extruder used in the first step is a co-rotation intermesingtype twin-screw extruder (Buhler Brothers Co., DNDL-40, Switzerland).The extruding conditions were as follows: screw speed—150˜400 rpm; feedrate—20˜60 kg/hour; moisture content—15˜40%; L/D ratio—20˜40. Either asingle screw or a twin-screw extruder can be used in the presentinvention, but a twin screw extruder providing greater shear force ispreferred for effectively solubilizing water-insoluble ginseng cellwalls.

The inventive process for preparing ginseng dietary fiber using theextruding process will be explained in detail below.

Process 1

Preparation of Ginseng Residue

Ginseng extraction was performed by adding solvents such as hot water,ethanol and methanol to raw materials such as red ginseng, white ginsengand Taeguk ginseng. Ginseng residue was recovered as a by-product afterthe ginseng extraction. Water and solvent remaining in the ginsengresidue were evaporated using a heating evaporator and the resulting dryginseng residue was ground into powder. Starch in the ginseng residuecan be removed by −a m ylase treatment. Ginseng residue without starchcan be used as a starting material with a higher dietary fiber content.

Process 2

Extrusion of Ginseng Residue

The ginseng residue prepared by the above-described process 1 was fedinto a twin-screw extruder with a L/D (length/diameter) ratio of 20˜40.The samples were extruded at a feed rate of 20˜60 kg/hr, a screw speedof 150˜400 rpm, and a moisture content of 15˜40%.

Process 3

Preparation of Water-soluble and Water-insoluble Ginseng Dietary Fiber

The extruded ginseng residue prepared in process 2 was added todistilled water to form a sample mixture containing 1˜10% (w/v) ginsengresidue and the sample was agitated for 40˜80 minutes. The sample wasthen centrifuged for 5˜15 minutes at 6,000˜9,000×g. Water-solubleginseng dietary fiber was obtained from the supernatant, whilewater-insoluble ginseng dietary fiber was obtained from the precipitate.The supernatant was filtered, and a 3˜5 times greater volume ofisopropanol was added to the filtrate. Then, after standing for 3˜5hours the precipitate was washed using isopropanol and acetone and driedat room temperature to thereby prepare water-soluble ginseng dietaryfiber.

In the present invention, the method for preparing oligosaccharides fromginseng residue includes the first step of dispersing the ginsengresidue into water and hydrolyzing the ginseng residue by the hydrolyticenzymes of the plant cell wall and; the second step of heating theenzyme solution to inactivate the enzymes and centrifuging to separatethe supernatant which includes oligosaccharides; and the third step ofpassing the supernatant through an ultrafiltrator and drying thefractions to prepare ginseng oligosaccharides with varying molecularweight.

A preferred example for preparing oligosaccharides from ginseng residueis illustrated in FIG. 3. A single commercial polysaccharide hydrolyticenzyme such as cellulase, hemicellulase or pectinase, or a mixture ofmore than one of these enzymes, was added to hydrolyze the ginsengresidue. In this example, Celluclast (Novo Nordisk, Demark) was used ascellulase; Ceremix L (Ceremic L Novo Nordisk, Denmark), Filtrase BR(Gist-Brocades, Netherlands), Ultraflo L (Novo Nordisk, Denmark) ashemicellulases; and Pectinex (Novo Nordisk, Denmark) as a pectinase.

After the enzyme reaction, ginseng oligosaccharides were obtained fromthe supernatant after centrifugation, and separated according tomolecular weight using an ultrafiltrator.

The inventive method for preparing oligosaccharides from ginseng residueusing polysaccharide hydrolytic enzymes will be explained in detailbelow.

Process 1

Preparation of Ginseng Residue

Ginseng extraction was performed by adding solvents such as hot water,ethanol or methanol to raw materials such as red ginseng, white ginsengand Taeguk ginseng. Ginseng residue was recovered as a by-product afterthe ginseng extraction. Water and solvent remaining in the ginsengresidue were evaporated using a beating evaporator and the resulting dryginseng residue was ground into powder. Starch in the ginseng residuecan be removed by −-amylase treatment. Ginseng residue without starchcan be used as a starting material with a higher dietary fiber content.

Process 2

Polysaccharide Hydrolytic Enzyme Treatment Process

The extruded ginseng residue prepared in the above-described process 1was added to distilled water to form a sample mixture containing1˜10%(w/v) ginseng residue and the sample was agitated for 40˜80minutes. One or a mixture of cellulase, hemicellulase and pectinase,which are commercially available polysaccharide hydrolytic enzymes, wasadded at a weight ratio of 1:1˜1:0.001 with respect to the ginsengresidue, and the sample was agitated at 30˜60° C. for 30˜480 minutes.The sample was then heated at 100° C. for 15 minutes to inactivate theenzymes and centrifuged at 5,000˜10,000×g for 10˜30 minutes to therebyobtain water-soluble ginseng oligosaccharides solution from thesupernatant. The precipitate can be used as water-insoluble dietaryfiber by drying the same.

Process 3

Fractionation of Ginseng Oligosaccharides Using an Ultra-fine Filter

The ginseng oligosaccharides solution prepared in process 2 above wassequentially passed through an ultrafiltrator for passing ginsengoligosaccharides with a molecular weight of 500˜5,000, and the filteredsolution was dried to thereby prepare ginseng oligosaccharides.

The method for preparing ginseng dietary fiber and oligosaccharides willbe explained in detail below. The scope of the claims of the presentapplication is not limited to the examples provided herein.

EXAMPLE 1 Preparation of Ginseng Dietary Fiber

Ginseng residue was fed into a twin-screw extruder with an L/D ratio of20. The extruder was operated at a screw speed of 250 rpm, a feed rateof 40 kg/hr, and a moisture content of 25%. 50 g of the extruded ginsengresidue was dispersed into 1 L of water and agitated for 1 hour,followed by centrifuging at 6,500×g for 10 minutes. The precipitate wasdried at room temperature to thereby prepare water-insoluble dietaryfiber. The supernatant was filtered, and 4 L of isopropanol was added tothe filtrate. After standing for 4 hours, the precipitate was washedusing isopropanol and acetone and dried at room temperature to therebyprepare water-soluble ginseng dietary fiber. The yield of water-solubleginseng dietary fiber was 15.4% based on the initial amount of theginseng residue. This result means that water-soluble dietary fibercomponents can be successfully isolated from the ginseng residue by theextrusion process.

Ginseng dietary fiber prepared according to the present invention can beapplied for preparing food products such as beverages, yogurt, bread,candy, health food, etc.

Experiment 1

Measurement of the Molecular Weight of Water-soluble Ginseng DietaryFiber Prepared in Example 1

The molecular weight of the water-soluble ginseng dietary fiber preparedin Example 1 was measured using gel permeation chromatography (GPC;Waters LC Module I, USA). The detector was a M410-RI equipped with aheating chamber and M2010 Millennium software was used for the dataanalysis. The column used was Ultrahydrogel 250 & 1000 linear column(Waters, USA). A mixture of 0.1M acetic acid and 0.1M NaCl was used as amobile phase, and its elution rate was 1.0 mL/min. FIG. 2 a is astandard curve of GPC using pullulan as a standard. FIG. 2 b shows thatthe weight average molecular weight of the water-soluble ginseng dietaryfiber prepared in Example 1 was 97,000.

EXAMPLE 2 Effect of the Extrusion Conditions on the Preparation ofGinseng Dietary Fiber

As shown in Table 1, the extrusion of ginseng residue to preparewater-soluble ginseng dietary fiber was repeated for different screwspeeds, feed rates and moisture contents. The production yield andmolecular weight of water-soluble dietary fiber were determined by themethods described in Example 1 and Experiment 1, respectively,

Table 1 shows that the production yield of water-soluble dietary fiberwas 12.6˜25.4%, and the molecular weight was 43,000˜126,000 depending onthe extruding conditions. In general, as the moisture content wasdecreased, the production yield was increased and the molecular weightwas decreased. This means that it is possible to produce ginseng dietaryfiber with various yields and molecular weights by controlling theextrusion conditions.

TABLE 1 Yield and molecular weight of water-soluble ginseng dietaryfiber for varied extrusion conditions (screw speed, feed rate andmoisture content) Screw speed Feed rate Moisture Yield Molecular (rpm)(kg/hr) (%) (%) weight 150 35 30 13.3 126,000 150 50 15 22.1 43,000 25035 30 14.2 93,000 300 35 30 14.8 89,000 250 40 20 20.6 67,000 250 30 1525.4 42,000 300 60 40 12.6 114,000 300 40 30 13.9 107,000 350 30 25 18.674,000 250 30 25 17.9 77,000 350 35 30 14.3 103,000 300 35 25 16.672,000 350 40 25 17.4 78,000 300 30 30 15.8 82,000 350 35 20 20.6 59,000300 40 20 20.4 64,000 400 35 25 17.7 82,000 400 20 40 14.6 98,000

EXAMPLE 3 Preparation of Ginseng Dietary Fiber by Changing the L/D Ratioof Extruder

Ginseng residue was fed into a twin-screw extruder with an L/D ratio of40, and extrusion was performed under the same conditions as inExample 1. By increasing the L/D ratio, the yield of water-solubledietary fiber was increased to 19.5%, while the molecular weight wasdecreased to 55,000. This result is interpreted as showing that theresidence time of the ginseng residue was increased in the extruder dueto the increased L/D ratio, which resulted in the increased productionyield of water-soluble dietary fiber. Therefore, it is also possible tocontrol the yield and the molecular weight of ginseng dietary fiber bychanging the L/D ratio of the extruder.

Comparative Example 1 Comparison Between the Yield of Ginseng DietaryFiber of the Present Invention and the Yield of Ginseng Dietary FiberPrepared by the Conventional Acid Treatment Process

50 g of ginseng residue was dispersed into 1 L of HCl solution, pH 1.8,and was agitated at 85° C. for 30 minutes and then filtered. Then, 4 Lof isopropanol was added to the supernatant. After standing for 4 hours,the precipitate was washed using isopropanol and acetone and dried atroom temperature to thereby prepare water-soluble ginseng dietary fiber.The yield of the water-soluble ginseng dietary fiber by the acidtreatment was 14.5%.

Therefore, comparing the yield of the extrusion process (15.4%) inExample 1 with that of the acid process (14.5%), it is clear that theextrusion process of the present invention is very effective inproducing water-soluble dietary fiber without using acid treatment.

EXAMPLE 4 Preparation of Ginseng Oligosaccharides

20 g of ginseng residue was dispersed into 500 ml of water and agitatedfor 30 minutes. Then, 2.0 g of Filtrase BR (Gist-Brocades, Netherlands)was added and agitated at 50° C. for 2 hours. After heating at 100° C.for 20 minutes to inactivate the enzyme, the resulting sample wascentrifuged at 6,000×g for 10 minutes, and then the supernatant wasfiltered and dried. The yield of ginseng oligosaccharides was determinedto be 56.7%. This result means that ginseng oligosacchrides can besuccessfully isolated from ginseng residue by polysaccharide hydrolyticenzymes.

Ginseng oligosaccharides prepared according to the present invention canbe applied to food products such as beverages, yogurt, candy, bread,health food, etc.

Experiment 2

Measurement of the Molecular Weight of Ginseng Oligosaccharides Preparedin Example 4

The molecular weight of the ginseng oligosaccharides prepared in Example4 was measured using gel permeation chromatography (GPC; Waters LCModule I, USA). The detector was a M410-RI equipped with a heatingchamber and M2010 Millennium software was used for the data analysis.The column used was Ultrahydrogel 125 & 250 linear column (Waters, USA).0.1M NaNO₃ solution was used as a mobile phase, and its elution rate was0.8 mL/min. FIG. 4 a is a standard curve of GPC using pullulan andlactose as standard materials.

As shown in FIG. 4 b, the weight average molecular weight of the ginsengoligosaccharides prepared in Example 4 was 1,050.

Experiment 3

The Proliferation Effect of Ginseng Oligosaccharides on IntestinalMicrobes

In this experiment, Bifidobacterium longum, isolated from Koreanexcrement in the Korea Food Research Institute, was used as anintestinal microbe (Korean J. Dairy Sci., 11(1), 16-25, 1989).Bifidobacterium longum was grown in a 20 mL MRS broth of Table 2 underan anaerobic condition and then used for this experiment. Anoligosaccharides free culture media was used as a control.Bifidobacterium longum was injected into the culture media with andwithout ginseng oligosaccharides, respectively, and the Bifidobacteriumlongum was cultured in an incubator at 37° C. The culture solution wassampled every two hours, and the light absorbance was measured at 660 nmto thereby obtain a growth curve.

FIG. 5 shows that, when ginseng oligosaccharides were added to theculture media, the absorbance was 2.95 after 20 hours. In contrast, theabsorbance was only 0.22 in the control culture broth without ginsengoligosaccharides. This means that ginseng oligosaccharides preparedaccording to the present invention are a catalyst to the growth ofintestinal microbes.

TABLE 2 Composition of MRS broth for Bifidobacterium longum culturesIngredient Amount Peptone 20 g Meat extract 10 g Enzyme extract 1 mLTween 80 2 g Ammonium citrate 5 g Sodium acetate 0.1 g MgSO₄ 7H₂O 0.05 gMnSO₄ 5H₂O 2 g Agar 15 g Ginseng oligosaccharides 20 g [Note] totalvolume of culture media 1 L, pH 6.0

EXAMPLE 5 Effects of the Type of Hydrolytic Enzymes Used for GinsengOligosaccharides Preparation

20 g of ginseng residue was dispersed into 500 ml of water and agitatedfor 30 minutes. Then, 0.1 g of each of Celluclast (Novo Nordisk,Denmark), Ultraflo L (Novo Nordisk, Denmark), Ceremic (Novo Nordisk,Denmark), Pectinex (Novo Nordisk, Denmark), and Filtrase BR(Gist-Brocades, Netherlands) were added to respective samples to prepareginseng oligosaccharides under the conditions shown in Table 3. Theproduction yield and the molecular weight of the prepared water-solubleginseng oligosaccharides were measured by the methods described inExample 4 and Experiment 2, respectively.

As shown in Table 3, the production yield of ginseng oligosaccharidesranged from 19.6% to 43.1% depending on the type of hydrolytic enzymesused, and the molecular weight was 1,180˜1,820. These results mean thatit is possible to produce ginseng oligosaccharides with various yieldsand molecular weights by varying the types of hydrolytic enzymes used.

TABLE 3 Yield and molecular weight of ginseng oligosaccharides fordifferent kinds of the hydrolytic enzymes Reaction Reaction ReactionYield Molecular Enzymes Temp. time pH (%) weight Celluclast 60° C. 1hour 5.0 20.5 1,820 Ceremix 30° C. 1 hour 6.5 38.9 1,530 Filtrase 50° C.1 hour 6.0 43.1 1,250 Pectinex 50° C. 1 hour 5.0 40.7 1,180 Ultraflo 50°C. 1 hour 6.0 20.3 1,470

EXAMPLE 6 Effect of Hydrolytic Enzyme Mixtures on GinsengOligosaccharide Preparation

Equal weights of Celluclast and each of the other enzymes used inExample 5 were mixed and used to treat ginseng residue under the sameconditions as in Example 4. The production yield and the molecularweight of the obtained water-soluble ginseng oligosaccharides weremeasured by the methods described in Example 4 and Experiment 2,respectively.

As shown in Table 4, the mixtures of Celluclast and the other enzymesresulted in oligosaccharide yields ranging from 33.1% to 50.4%, which ismuch higher than the 20.5% yield of Celluclast alone obtained in Example5. This result means that appropriate enzyme mixture systems can greatlyimprove the production yield of ginseng oligosaccharides.

TABLE 4 Yield and molecular weight of ginseng oligosaccharides based onthe mixing of the hydrolytic enzymes Enzyme Reaction Reaction ReactionYield Molecular mixture Temp. time pH (%) weight Celluclast + 40° C. 1hour 6.0 38.5 1,670 Ceremix Celluclast + 50° C. 1 hour 6.0 48.6 1,320Filtrase Celluclast + 50° C. 1 hour 6.0 47.2 1,120 Pectinex Celluclast +50° C. 1 hour 6.0 33.6 1,420 Ultraflo Celluclast + 50° C. 1 hour 6.050.4 980 Filtrase + Pectinex

EXAMPLE 7 Fractionation of Ginseng Oligosaccharides Using anUltrafiltrator

The ginseng oligosaccharides prepared in Example 4 were sequentiallypassed through an ultrafiltrator for passing ginseng oligosaccharideswith molecular weight 500˜3000 and then dried. As shown in Table 5, itis possible to prepare ginseng oligosaccharides with various ranges ofmolecular weight.

TABLE 5 Yield of ginseng oligosaccharides depending on the molecularweight fractions after ultrafiltration Molecular Yield (%) weightfraction Celluclast Ceremix Filtrase Pectinex Ultraflo >3000 9.4 10.68.9 8.1 7.4 1,000˜3,000 30.9 28.5 15.6 20.7 25.3  500˜1,000 39.1 40.752.1 53.4 47.6 <500 20.6 20.2 23.4 17.8 19.7

Industrial Applicability

The present invention provides methods of producing water-solubledietary fiber and oligosaccharides from ginseng residue using anextrusion process and polysaccharide hydrolytic enzymes, respectively.Since physiologically active dietary fiber and oligosaccharide materialscan be effectively produced from ginseng residue without chemicaltreatment, the methods of the present invention areenvironment-friendly.

In addition, it is possible to prepare ginseng dietary fibers withvarious ranges of molecular weight by varying extrusion conditions. Itis also possible to prepare ginseng oligosaccharides with various rangesof molecular weight by using different types of hydrolytic enzymes andvarying ultrafiltration conditions.

1. A process for preparing water-insoluble ginseng dietary fiber,comprising: (a) obtaining a ginseng residue produced as a by-product ofginseng extraction, and drying and grinding the ginseng residue; (b)feeding the dried and ground ginseng residue into a twin-screw extruderwith a L/D ratio of 20˜40 and operating the twin-screw extruder at ascrew speed of 150˜400 rpm, a feed rate of 20˜60 kg/hr and a moisturecontent of 15˜40% to produce an extruded ginseng residue; (c) adding theextruded ginseng residue to water at a concentration of 1˜10% (w/v) toprepare a sample, agitating and centrifuging the sample to produce asupernatant and a precipitate; and (d) drying the precipitate obtainedby centrifugation to obtain water-insoluble ginseng dietary fiber. 2.Water-insoluble ginseng dietary fiber prepared by the process ofclaim
 1. 3. A process for preparing water-soluble ginseng dietary fiber,comprising: (a) obtaining a ginseng residue produced as a by-product ofginseng extraction, and drying and grinding the ginseng residue; (b)feeding the dried and ground ginseng residue into a twin-screw extruderwith a L/D ratio of 20˜40 and operating the twin-screw extruder at ascrew speed of 150˜400 rpm at a feed rate of 20˜60 kg/hr and a moisturecontent of 15˜40% to produce an extruded ginseng residue; (c) adding theextruded ginseng residue to water at a concentration of 1˜10% (w/v),agitating and centrifuging the sample to produce a supernatant and aprecipitate; and (d) filtering the supernatant to obtain water-solubleginseng dietary fiber and a filtrate, adding isopropanol to thefiltrate, the volume of isopropanol added being 3˜5 times greater thanthe volume of the filtrate, obtaining a second precipitate, washing thesecond precipitate with isopropanol and acetone, drying the secondprecipitate and obtaining further water-soluable ginseng dietary fiber.4. Water-soluble ginseng dietary fiber prepared by the process of claim3.
 5. The water-soluble ginseng dietary fiber of claim 4, wherein saidfiber has a molecular weight of 43,000-126,000.